Circuit interrupting apparatus



May 18, 1943 H. A. TRIPLETT CIRCUIT INTERRUPTING' APPARATUS 2 sheds-sheet 1 Filed April 27, 1942 'auf g5. l

0 W// l L Y W? H. A. TRIPLETT CIRCUIT INTERRUPTING APPARATUS Filed April 27, 1942 2 Sheets-Sheet 2 May l18, 1943 Patented May 1 8, 1943 ACIRCUIT INTERRUPTING APPARATUS llugh A. Triplett, Wilm Schweitzer & Conrad, I

poration of Delaware ette, Ill., assignor to nc., Chicago, Ill., a cor- Appiication April 27, 1942, Serial N0. 440,628

(Cl. 20o-120) 9 Claims.

,My invention relates generally to circuit interrupting apparatus and it has particular relation to such apparatus in which means are especially provided for interrupting relatively low current arcs. The present invention relates to and constitutes an improvement over the circuit interrupting apparatus disclosed in my co-` pending application, Serial No. 372,217, iiled December 30, 1940.

One of the objects of my invention is to provide for releasing an arc extinguishing fluid into the space occupied by an arc between relatively movable apart terminal members when one of the terminal members reaches a predetermined position.

Another object of my invention is to provide a limited degree of relative movement between a reservoir containing the material which when released discharges an arc extinguishing fluid into an arc space and the rod-like terminal such that the are extinguishing fluid is released when the relative movement takes place.

A still further object of my invention is to provide for holding the material which is discharged in the form of a :fluid into the arc space in a replaceable capsule so arranged as to be readily renewable.

It is also an object of my invention to provide for discharging the arc extinguishing iiuid into a bore in arc extinguishing material for assisting in extinguishing the arc and scavenging the walls of the bore by blowing out products of the arc deposited thereon which are likely to facilitate restriking of the arc.`

Other objects of my invention will, in part, be obvious and in part appear hereinafter.

For a more complete understanding of the nature and scope of my invention reference can v be had to the following detailed description taken in connection with the accompanying drawings in which;

Figure 1 is a longitudinal sectional view of the upper end portion of a high voltage solid material fuse construction which can be employed in practicing the present invention;

Figure 2 is a longitudinal sectional view, at an enlarged scale. of the lower end portion of the fuse construction shown in Figure 1, illustrating how the present invention can be incorporated therein;

Figure 3 is a longitudinal sectional view of the replaceable cartridge for the construction shown in Figures 1 and 2, the cartridge being shown in the blown condition with the arc extinguishing fluid being discharged into the arc space; and

Figure 4 is a view, at an enlarged scale, of the lower end portion of the cartridge shown in Figure 3, the relative positions of the parts being those occupied at the instant that the arc extinguishing fluid is released from the replaceable capsule.

Reference will first be had to the fuse construction shown in Figures 1 and 2 of the drawings. The fuse construction there shown is generally similar to the fuse construction shown in my copending application, Serial No. 365,232, filed November 12, 1940. It comprises a suitable insulating housing I0, such as glass or porcelain, having external terminals Il and I2 at its ends. It will be understood that the terminals Il and l2 are arranged to be mounted in suitable terminal contact clips which, in turn, are connected to line conductors in a conventional manner. Integrally formed with the upper terminal Il is a condenser housing, shown generally' at I3, which houses a condenser assembly for cooling and condensing the products incident to the formation of the arc that is drawn on operation of the device. Since the construction of the condenser is set forth in detail in my copending application, Serial No. part of the present invention, it will not be further described herein.

The insulating housing l0 is arranged to receive and the terminals Il and l2 are arranged to be interconnected by a replaceable cartridge assembly shown generally at I4 and illustrated in more detail in Figure 3 of the drawings. It

will be observed that the cartridge I4 comprises a housing il of insulating material having a terminal member i8 at its upper end for connection to the terminal Il at the upper end of the insulating housing l0. Within the insulating housing I1 there is provided a liner of solid arc extinguishing .material formed by a number of rings i9 of insulating material such as magnesium borate or boric acid. .The rings i9 are i stacked one above the other to provide a bore 20. The material employed for forming the bore 20 is preferably such as will evolve a relatively large amount of arc extinguishing 'materialwhen subjected to the heat of an arc.

A rod-like terminal member 2| is mounted for longitudinal movement in the bore 20. It is restrained from such movement by means of a strain wire 22, Figure 1, which is shunted by a fusible element 23, preferably a silver wire, which directly interconnects the upper end of the rodlike terminal member 2l and the terminal member I8. It will be understood that when the 365,232, referred to, and forms no fusible element 23 and the strain wire 22 blow, due to'excess ilow of current therethrough, an arc will be formed between the terminal members IB and 2l which it is desired to extinguish as rapidly as possible. This arc is drawn into the bore as the rod-like terminal member 2l is retracted therein.` If this arc is formed as the result of relatively heavy current ow so that the bore 20 is substantially illled, relatively little dil= culty is encountered in extinguishing it since it is of sulcient size to cause the evolution of a relatively large quantity of arc extinguishing medium from the walls forming the bore in the solid arc extinguishing material I9. However, when the arc formed in the bore 2u has a relatively small amount of current iiowing through it, proportionately less heat is generated and it is often the case that an insumcient amount of arc extinguishing material is evolved to quickly extinguish the arc and deionize the arc space. Such a small current arc may not be extinguished until the rod-like terminal member 2l is retracted substantially the entire distance through which it normally moves. Even then, under certain power factor and voltage conditions, the arc may still.

persist. As a result some damage may be caused by the continued existence of the small current arc. It is to the provision of means for extinguishing particularly small current arcs in a circuit interrupter otherwise well adapted to extinguish heavier current arcs that the'present invention is directed in part.

It will be observed that the rod-like terminal 2l is arranged to be retracted by a coil compression spring 2d which reacts between a contact member 25 and a collar 26 carried by and secured to the upper end of a metallic sleeve 2l. 'Ihe metallic sleeve 2l is slidably mounted within a conducting sleeve 28 which serves to interconnect the contact member 25 and the lower terminal l2, Figure 2. on the insulating housing lil. An extension 29 d'epends from the conducting sleeve 28 for a pur pose which will be presently apparent.

The rod-like terminal member 2l is connected by means of a exible conductor 33, Figure l, having a protective covering of non-magnetic wire 34, to a strap 35 which,`as shown, is connected to the contact member 25. The flexible conductor 33 is looped over a pulley 36v which is mounted to move with the metallic sleeve 2l as urged by the coil compression spring 2d. 'With this construction the terminal member 2l moves at twice the speed that the metallic sleeve 2l moves and the arc formed between the terminal members i8 and 2l is correspondingly extended.

As shown in Figures 2 and 4, the pulley' is rotatably mounted on a pin 3l which extends through a pair of links 38 that are secured by a pin 39 to the head 40 of a bolt 4I. sleeve 42 surrounds the shank of the bolt 4I and provides a strut against which lock nuts 43 are Cil released constitutes an arc extinguishing uid that is capable of assisting in extinguishing the arc formed in the bore 2G and deionizing the space occupied by the arc. The reservoir or capsule 52 can be purchased under the trade name "Sparklet although other similar reservoirs or capsules can be employed if desired. The upper end of the reservoir or capsule 52 is sealed by a diaphragm As previously indicated, the bolt 4l and accompanying sleeve 42 are slidably mounted in the extension 44 of the collar 45. There is then a certain amount of lost motion between the bolt di and the reservoir or capsule 52. A coil compression spring 55 is provided for maintaining the bolt 4l and the reservoir or capsule 52 in spaced relation prior to operation of the device. At the lower end of the bolt 4l there is provided a needle 56 which is arranged to puncture or rupture the diaphragm 5d so as to permit the escape of the arc extinguishing uid from the reservoir or capsule 52 through suitable apertures 5l, Fig- A metallic tightened to provide a unitary construction. It

will be observed that the sleeve 42 which is mov- 'able with the bolt 4l is slidably mounted in a ure e, in the collar 55. As shown in Figure 3 of the drawings, this arc extinguishing iluid is discharged into the bore 2li. The fluid is discharged into the bore 2@ under suillcient pressure and in sumcient quantity so as to sweep out the low current arc which may persist therein after the,

rod-like terminal member 2l has substantially completed its downward movement. The continued discharge of the uid also acts after interruption of any magnitude of fault current to scavenge the walls of the bore 26 so as to blow out any remaining products of the arc which might form a conducting path between the terminals l@ and 2l which might facilitate restriking. This restoration of the dielectric strength of the walls of the bore is important, particularly in high voltage installations as will be readily appreciated by those skilled in the art.

When the rod-like terminal member 2l is released upon blowing of the 'fusible element 23 and strain wire 22, the coil compression spring 2d expands and moves the metallic sleeve 2l downwardly. The reservoir or capsule 52 in the cap 5l also moves downwardly. After the cap El is moved downwardly a slight distance through the extension 29, as shown in Figure 2, a diaphragm 5e is ruptured and the cap 5l continues to move downwardly through the open lower end of the extension 29 to the position shown in Figure 3 of the drawings. This then provides an indication that the'fuse has operated and should be replaced with an unblown cartridge.

The reservoir or capsule 52 continues to move downwardly together with the rod-like terminal member 2lv although the latter moves at a speed which is twice that of the former. This movement continues until the collar 26 engages the upper end ofthe extension 29 whereupon further downward movement of the sleeve 29 and reservoir or capsule E2 is prevented. However, the rod-like terminal member 2| continues to move downwardly because of its inertia and, since the bolt 4l is slidably mounted in the extension 44 a somewhat further downward movel capsule 52 as previously de# asiaave The cartridge I 4 can be readily restored to its initial condition by replacing the strain element 22 and the fusible element 2l and by replacing the blown reservoir or capsule l2 with an unblown one. In the event that the bore 20 in the solid arc extinguishing material I9 has been injured or damaged because of the circuit interruption, then it may be necessary to replace some orall of the rings of this arc extinguishing material.

Since it is obvious that other embodiments of my invention can be made without departing from the spirit and scope thereof, it is intended that all matter shown in the accompanying drawings and described hereinbefore shalt be construed as illustrative and not in a limiting sense.

I claim as my invention:

l. In circuit interrupting apparatus, in combination a body of arc extinguishing material having a bore, a pair of relatively movable terminal members between which an arc is adapted to be formed, one of said terminal members ceing located adjacent one end of said bore and the other being rod-like in character and movable through said bore, a. reservoir for holding material which when released is in the form ci an arc extinguishing fluid, and means for releasing said fluid into said bore and the arc space when said rod-like terminal member reaches a speciiic position for assisting in extinguishng an arc that may exist between said terminal members and for blowing out of said bore products of the arc deposited on the surface thereof and likely to facilitate restriking.

2. In circuit interrupting apparatus, in combination a body of arc extinguishing material hav. ing a bore, a pair of relatively movable terminal members between which an arc is adapted to be formed, one of said terminal members being iocated adjacent one end of said bore and the other being rod-like in character and movable through said bore, a reservoir for holding material which when released is in the form of an arc extinguished iluid, and means controlled in accordance with the movement of said rod-like terminal member for releasing said fluid into said bore and into the space ocupied by an arc between said terminal members for assisting in extinguishing the same and for blowing out of said bore products of the arc deposited on the surface thereof and likely to facilitate restriking.

3. In circuit interrupting apparatus, in combination a. body of arc extinguishing material having a bore, a pair of relatively movable terminal members between which an arc is adapted to be formed, one of said terminal members being located adjacent one end of said bore and the other being rod-like in character and movable through said bore, a reservoir for holding material which then released is in the form of an arc extinguishing fluid, releasable means retaining said material in said reservoir, and means for releasing said releasable means when said rodlike terminal member is in a specified position whereby said arc extinguishing fluid flows into said bore and into the space occupied by the arc for asisting in extinguishing the same and for blowing out of said bore-products of the arc deposited on the surface thereof and likely to facilitate restriking.

4. In circuit interrupting apparatus, in combination a body of arc extinguishing material havmembers between which an arc is adapted to be formed, one of said terminal members being located adjacent one end of said -bore and the other being rod-like in character and movable through said bore, a reservoir for holding material which when released is in the form of an arc extinguishing fluid, said reservoir -being movable together with said rod-like terminal member, releasable meansretaining said material in said reservoir, and means for releasing said releasable means when said rod-like terminal member reaches a predetermined position kwhereby said are extinguishing fluid flows into said -bore and into the space occupied by the arc for assisting in extinguishing the same and scavenging the surface of said bore.

5. In circuit interrupting apparatus, in combination a |body of arc extinguishing material havinga bore, a pair of relatively movable terminal members between which an arc is adapted to be formed, one of said terminal members being located adjacent one end of said bore and the other being rod-like in character and movable through said bore, a reservoir for holding material which when released is in the form of an arc extinguishing fluid, said reservoir being movable together with said rod-like terminal member, means providing relative movement between said reservoir and said rod-like terminal mem-ber, releasable means retaining said material in said reservoir, and means for releasing said releasable means in response to said relative movement between said reservoir and said rod-like terminal member whereby said arc extinguishing duid flows into said bore and into the space occupied by the arc for assisting in extinguishing' the same and for blowing out of said bore products of the arc deposited on the surface thereof and likely to facilitate restriking.

6. In circuit interrupting apparatus, in combinationa body of arc extinguishing material having a bore, a pair of relatively movable terminal members between which an arc is adapted to `be formed, one of said terminal members being located adjacent one end of said bore and the other being rod-like in character and movable through said bore, a reservoir for holding material which when released is in the form of an arc extinguishing fluid, a diaphragm sealing said reservoir, and means controlled in accordance with the movement of said rod-like terminal member for rupturing said diaphragm to release said fluid into said ibore and into the space occupied by an arc between said terminal members for assisting in extinguishing the same and for blowing out of said bore products of the arc deposited on the lllirface thereof and likely to facilitate restrikrI. In circuit interrupting apparatus, in combination a body of arc extinguishing material having a Ibore, a pair of relatively movable terminal members 4between which an arc is adapted to be formed, one of said terminal members being located adjacent one end of said bore and the other being rod-like in character and movable through said bore, a replaceable capsule containing material which when released is in the form of an arc extinguishing fluid, said replaceable capsule being movable together with said rod-like terminal member, a diaphragm sealing said capsule, and means for rupturing said diaphragm as a resultv of movement of said rod-like terminal member to a predetermined position to'release said arc extinguishing fluid into said bore and ing a bore, a pair of relatively movable terminal the arc space for assisting in extinguishing an arc that may exist between said terminal members and scavenging the surface of said bore.

8. In circuit interrupting apparatus, in combination a body of arc extinguishing material having a bore. a pair of relatively movable terminal members between which an arc is adapted to be formed, one of said terminal members being located adjacent one end of said bore and the other being rod-like in character and movable through said bore, a replaceable capsule containing material which when released is 1n the form of an arc extinguishing duid, a diaphragm sealing said capsule, and means for rupturing said diaphragm to release said arc extinguishing uid into said bore and the arc space for assisting in extinguishing an arc that may exist between said terminal members and for blowing out of said bore products oi the arc deposited on the surface thereoi and likely to facilitate restriking.

9. In circuit interrupting apparatus, in com-bination a body of arc extinguishing material having a Ibore, a pair of relatively movable terminal members between which an are is adapted to be formed, one oi' said terminal members being located adjacent one end of said bore and the other being rod-like in character and movable through l@ capsule and rod-like terminal member being biased apart, means for arresting movement of said capsule when it has Ibeen moved to a 4specified position while said rod-like terminal member continues to move, and means operated as a result i l5 of movement of said rod-like terminal. member after movement of said replaceable capsule has been arrested for rupturing said diaphragm to release said arc extinguishing uid into said bore and the arc space, for assisting in extinguishing 20 an arc that may exist between said terminal members and for blowing out of said bore products ot the arc deposited on the surface thereof and likely to -facilitate restriking.

HUGH A. I'RIPLETT. 

